Design, disseminate and evaluate a computer-based ambulatory information system (COSTAR 5) that will 1) facilitate the management of an ambulatory practice; 2) assist the health care provider in patient care; and 3) stimulate improvement in ambulatory care by providing an exploitable database for quality assurance and health care research. Methods for accomplishing this include extending Level One COSTAR 5 to facilitate total elimination of the paper record, to provide better communication of medical data to primary care providers, and to make the system more responsive to large practices with prepaid patients. New capabilities that will expand the types of uses for which COSTAR would be applicable will be added (e.g., protocol-determined data capture,) as well as means for exploiting the database to meet practice-specific needs (e.g., quality assurance modules and a general purpose Query Language). Because the primary objective is to achieve a generalized system that can be used in a wide variety of ambulatory facilities, and because this system has been designed to accommodate considerable on-site customization by non-programming staff, means for assuring and supporting exportability must be included. We propose to develop a comprehensive guide to customizing and installing COSTAR 5 (in what-ever modular configuration is chosen by the practice), supported by detailed communication and education materials. Additionally, the present uniquely coded directory of terms will be replaced by nationally recognized standardized directories, and a User's Group will be initiated and supported. Means for evaluating the effectiveness as well as the marketability of COSTAR 5 will be developed and carried at test sites using the following three strategies: 1) comparison with the manual system using criteria such as cost and reliability; 2) impact of the system on various types of practices, and 3) user feedback via survey forms.